Pulley



June 3. 1924, 1,496,032

` F. H. SLEEPER y PULLEY F'led May 25. 1923 FRANK H. SLEEPER ATTORNEYS@JMW Patented June 3, 1924s UN IT E D? STAT j.

FRANK H. SLEEPER, OF VJ'ORCESTER, MASSACHUSETTS; ASSIGNOR '.IO` SLEEPER&,

HARTLEY, INCL, OF WORCESTER, MASSACHUSETTS, A CORPORATION-OF. MASSA-CH'USETTS.

PULLEY.

Application filed-May 25, 1923. SerialrNo. $451,477.

To all whom z5 may concern.'

Be it known that I, FRANK H. SLE-erna, a citizen of the Dominion ofCanada, residing at Worcester, inthe Vcounty of W'orcester and StateoflVfassachusetts7 haveinvented a new and useful Pulley7 of which thefollowing is a specification. f

This invention relates to a* pulley for transmitting power andtheprincipal ob- '10 ject thereof is to so construct the pulley thatits'diameterv will be automatically varied in accordance with variationsin the load.'

More specifically the invention involves the provision of a drivingpulley for' a belt transmission so arranged that when the'loadtransmitted is increased the diameter of the pulley willbe reduced toslow down lthe speed, and when the load is reduced the diameter ofQthepulley will be increased to increase the speed of the shaft to which thepower is transmitted by it, or the provision of a driven pulleyconstructed in substantially the same way butso arranged that when the fvtorque on its shaft increases the diameter of the pulleyincreases, sothat its speed will decreasev and vice versa. Y.

The invention also' involves features of constructionby which theseresults are se- Y cured. v

Reference istok be had to the accompanying drawings in which-'- rFig.1`is an elevationY of a driven pulley constructed in accordance withthis inven-V tion` showing half of it in central section;

Fig. 2 is a side elevation of the same vpartly broken away to showinterior construction; v

Fig. Bjis a side view of the guide disc thereof;

Fig. 4 is a similarfview of one of the sections of the pulley rim andconnected parts;

Fig. 5 is a view similar to Fig. 1 showing a driving pulley constructedon the same principle; and

Fig, 6- is aside view showing one way in whichv the driving and drivenpulleys illustrated in the other figures can be used for transmittingpower.

Referring first to the firstl four figures,

I have shown the invention as applied toa driven pulley A. In this formthe driven shaft: 10 has keyed upon Vit the hub of a flat disc 11i Thisdisc is provided with a seriesof cam slots12, alllocated at equaldefinite angles to radial linesat thosepoints.

litotatably mounted on the driven shaft 1.0 is the hub 13 of the pulley.l This hub isin tended to be connected with the shaft throughthe discllonly. It Vis shown as or projections 16. Iyhavev shown-notches 1T at theends of these guides forV a purpose: to

be described. l Y

Mounted to4 move freelyv in the guides 15..

are a series of slides 18. Each one of these has a pulley rim sectionl9,preferably in-` tegrally mounted on its end, andfthese sec- Y tionstaken together constitute the entire,

rim of thefpulley. These slides arelocated in the guides 15 sothat theycan move radi-v ally therein for the purpose ofincreasing anddecreasingthe diameter ofy the. pulley. Each slide is provided with aprojection or stud. 20 on which4 is rotatably mounted a cam roll 21. Thenumber of thesev slides isl equal to the number 'of cam 'slotsl 12 and.each of these rolls 21 is" placed inione of the cam slots. A

eoY

A-tthe rearvofv .each slide is shown a web 22 for which the notches 17are provided. One end. ofa spring 23 is secured, to the web, the otherendl being securedto aprojection 24 on the hub 13. These springsasshownin these figures are arranged radially and. they are extensionsprings in this case.

tend toy resist all-decrease in the speed of transmission. The springs23 tend to hold the slides intoward the center and-in that way they tendto resist increase in the size of the driven pulley andconsequentreducvf tion of the speed ratio. In this case they also resist theaction of centrifugal force if the pulley is driven fast enough ,tobring that intoV 'play sufficiently to move these sections. :I havedescribedonly two'springs 23 and 33both of them radial, but it will beunderstood that I can employ' any means for the speed ratio. f

It will' be seen that-power 1s transmitted Any spring or other means canbe used that will fromI a belt running over therim 19 ofthe pulley Athrough the several slides 18 to the rolls 2l, the rolls, on account otlengaging the slanting surfaces of the slots l2 will move outwardly onany increase in lcad or torque. Therefore the belt willV transmit itspower to the disc l1 and thus to the driven shaft l() at a slower speed.This change in speed is governed automatically by the resistance on thedriven shaft.

It will be seen further that whenever less resistance is placed on theshaft l0 the rolls, on account of the cam action of the walls ofthef'slots l2 vwill tend to move inwardly. They can do this only by arelative motion in the slotstowar'd the inner ends thereof. The effectof this is to move the whole slide each case nearer the center andreduce the diameter of the pulley. As this pulley beingV described nowis a driven pulley that will increase the speed rat-io and drive thepulley faster. It is to be noted that, disregarding centrifugal forcefor the present. the only cause for the change in the diameter of thepulley is the change in the torque on theshaft. I

Although I have mentioned centrifugal y force I .wish itto be understoodthat ordinarily I do not intend to drive this pulley fast enough to havethe centrifugal force eX- ert any appreciable influence on the diameteiof the pulley.

In applying this invention to a driving f pulley B as shown in Fig. 5all the elements are made in the same way preferably except that thespring 33 is va compression spring on a rod 34 which is radial. Now theshaft is the driver and the rim the driven element of this pulley.Therefore, an increase in the power required will tend to pull thesections of the vpulley inwardly and reduce its-size,

gledrive and shown the power transmitted i from one to the other by thebelt l) with a take-np pulley C bearing on the belt between thein. Thisprovides for securing the desired results by the action of both puleysvention as expressed in the claims.

co-operating with each other. Each one acts in vthe manner abovedescribed and their combined action secures the desired result.

Although'I have illustrated and described only two forms of theinvention I am aware of the fact that other modifications can be madetherein by any person skilled in the art wi'thoutdeparting from thescope of the in- Therefore I do not wish to be limited to the details ofconstruction herein shown and described, but what I do claim isV1..'I`he combination with a shaft and a sectional rim expansion pulleyloosely 1mounted thereon, of a disc iXed on the shaft,

the pulley sections and the disc having angularly located slots androlls engaging in the slots, whereby relative rotation of the pulley andshaft will change the size'of the pulley, and yielding means forresisting motion or the pulley sections in a direction which woulddecrease the speed of transmission ofV rotation between the shaft andrim, whereby changes in torque will change the size of the pulley Abymoving the rim sections, and

yielding means for assistingmotionof the rim sections in directiontoincrease the speed of transmission.

3. In an expansible pulley, the combination with a pair of hub members,one tightV and the other loose lon the pulley shaft, one Y having aseries of radial guides, of acorresponding series of rigid rim sectionsspaced apart at their ends and eachhaving a slide the sections in adirection to increase the speed ratio,pand means independent of thesprings for transmitting the power and for moving the rim sectionsradially in a' direction to increase the speed ratio when the loaddecreases.

4. In an expansible pulley, the combination with apair of hub members,one tight and the other loose on the pulley shaft, the loose` one havinga series of radial guides', of corresponding series of rigid rimsections Sli spaced Vapart at their ends'and each having a slideengaging the respective guides and capable of moving radially thereon, acorresponding number of radially arrangedV springs connecting the rimsections'with the loose hub member and always tending to move'thesections in a direction toincrease the speed ratio, and means constantlyconnected with the tight hub member for moving the rim sections radiallyin a direction to decrease the speed ratio when the load increases.

5. The combination with a shaft and an eXpansible driven pulley looselymounted thereon, of a member fixedly secured to the shaft, and meansadjustably and'constantlyV connecting said member with the vpulley forautomatically increasing the diameter of the i pulley upon theapplicationof an increased load and decreasing the diameter upon areduction of the load and yielding means for constantly tending todecrease the size of the pulley.

6. The combination with an expansible pulley and its shaft on which thepulley is mounted loosely, of a disc fixed on the shaft,

and means connecting the pulley and disc for transmitting power, saidmeans having -co-operating parts for changing the diameter of the rimautomatically in a direction to increase the speed of the driven shaftwhen the load decreases and decrease it when the load increases.

7. ln a pulley, the combination with a disc tight on its shaft, a hubloose on the same shaft, the disc having cam, slots `arranged at anangle to a radial direction,

slides mounted to move on the hub, and eachv having a section of apulley rim thereon, a projection on eacli slide entering one of saidcain slots and fitting it, said slots each being pitched in thedirection to cause said projections to move in a direction to increasethe speed of the Adriven shaft whenever the torque is reduced anddecrease it when the Y torque is increased, and yielding means forresisting decreases in the speed ratio. Y 8. ln a pulley, thecombination with `a Vdisc tight on its shaft, a hub loose on the sameshaft and having radial guides, the disc having an equal number of camslots, slides mounted to niove radially outwardly and inwardly in saidguides, and each having a section of a pulley rim thereon, a projectionon each slide entering one of said cani slots and itting it, said slotseach being arranged at an angle to a radial directionl pitched in thedirection to cause said projec-v tions to move in a ,radial direction toincrease the speed of the driven shaft whenever the torque is ,reducedand decrease` it whenthe torque is increased, and yielding means forresisting decreases in thespeed ratio'.

9. The combination with a drivingv and' a driven shaft, of a disc tighton eachV shaft,

a hub loose on eacli shaft and having guides, the disc having an equalnumber l of cam slots, slides mounted to move outwardly and inwardly insaid guides, and each having a section of a pulley rim thereon, aprojection on each slide entering one of said cam slots,

said slots each being arranged at an angle Y l FRANK H. sLiiEriiR.

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